I've had a large taro plant potted & placed in my pond for 3 years now. It stays in the pond during the summer and I overwinter it in the garage (in it's same pot). About 8-10 feet away I always have 2 pot of oxalis (the green ones with the burgundy centers). When it warmed up, the taro went back in the pond. One oxalis plant went in its usual spot and the other one I dumped in a newer garden bed. A few weeks pass and I see black taro leaves coming in amongst the potted oxalis plant! I walk back to the garden where I dumped the other pot of oxalis and there were taro leaves popping up there as well. I did not transplant any taro root.....did they spread by seed?